Jet impact pulverizer



4 N. H. ANDREWS v JET IMPACT PULVERIZER Filed July 19, 1944 I5Sheets-Sheet 1 F G U R E INVENTOR NORWOOD H. ANDREWS.

Nov. 8, 1949 N. H. ANDREWS JET IMPACT PULVERIZER s She ets-Sheet 2 FiledJuly 19, 1944 HGURE- 2' NORWOOD H. ANDREWS INVENTOR N. H. ANDREWS JETIMPACT PULVERIZER Nov. 8, 1949 Filed July 19, 1944 3 Sheets-Sheet 3FIGURE lNV ENTOR NORWOOD H. ANDREWS.

. from ten to twelve per Patented Nov. 8, 1949 2,487,088 JET IMPACTPULVERIZER Norwood H. Andrews. Moorestown, N. 1., asslgnor,

by mesne assignments,

pany, New York, N. Y.,

ware

The Micronizer Coma corporation of Dela- Application July 19, 1944,Serial No. 545,667 11 Claims. (Cl. 241-40) This invention relates to anapparatus for reducing the particle size of partially comminutcd solids.It is concerned with equipment for grinding solids which may containadsorbed or absorbed water and is advantageously applied to finelypulverizing anthracite culm, clay, paint pigments and other similarmaterials.

The following will illustrate a typical application of my improvedapparatus. In screenings from anthracite workings there are literallymillions of tons of material available which are called anthracite culmin the industry. This culm ordinarily contains about thirty per cent ofash and cannot satisfactorily be burned on grates until it is treated toreduce the ash content to at least ten per cent. This can beaccomplished by a flotation separation, but the fraction of reduced ashcontent then carries cent of water. Attempts to dry such potential fuelresult in a considerable loss, due to the carrying out of the fines inthe drying air stream, as well as exceeding costs permissible in thepreparation of a fuel. Attempts to dry the culm by methods other thanpassing a heated gas over or through it have met with little success dueto the difficulty in such other methods of handling the large quantitiesof materials usually present.

Likewise, there are many situations in other industries requiring thereduction in size of solid particles from either a wet or a dry,original state. Processing earth materials, such as various clays,processing paint or ink pigments, and processing paper coating materialsare examples of industries having these requirements. Theseillustrations will suggest others.

I have now devised asimple apparatus having no moving parts wherebyparticles of solids, such as those named. can be reduced in size fromthat in which the solids are originally obtained. Furthermore, theapparatus is capable of using a wet materialfsuch as washed culm,directly without the necessity of first drying carefully.

It is accordingly among the objects of the invention to provide anapparatus for treating partially comminuted solids, containinginsuflicient water to produce a slurry, which apparatus will yield adry, finely divided, product in uniform size ranges.

It is a further object of the invention to provide apparatus which iscapable of grinding, drying, and classifying partially comminuted solidsin which no moving parts are required.

Another object of the invention is to provide n apparatus for grindinganthracite ca m and 2 other solids containing adsorbed water whicheconomically produces a uniformly sized, finely divided product.

Still a further object of the invention is to provide an apparatuscapable of handling large quantities of relatively coarse solids in ashort time cycle and with equipment having a high throughput in poundsper hour per square foot of drying, grinding and classifying area.

In the drawings:

' Figure 1 illustrates diagrammatically, in side section elevation, apreferred form of apparatus in which my invention may be practiced.Figures 2 and 3 illustrate diagrammatically, in side section, elevationalternative forms of apparatus in which my invention may be practiced.

The method which I have invented includes feeding the solid (wet or dry)at a fairly uniform rate to an aspirating zone from which it enters intoa high velocity gas jet or jets. The gas is preferably heated wheredrying is to be accomplished but otherwise heating is not essential.

The solid particles are then projected by the gas stream against asuitable blockor anvil upon which they are shattered. The gas stream,carrying the said particles, is then led out of the impact zone andintroduced tangentially into a classifying zone surrounding the path ofintroduction of the solid into the high-pressure gas. In the classifyingzone the particles of the solid which have been reduced to the desiredsize are carried out of the zone and particles larger than the desiredsize drop out of the gas stream and downward into the raw feed, thusreturning such oversize particles to the high-pressure gas stream andsubjecting them to further processing.

The particular series of steps which comprise my invention include:

Releasing a' gas under high pressure through an orifice to create a highvelocity flowing gas stream; introducing solid to be ground into a highvelocity gas jet in an aspirating zone; interposing a block in the pathof the high velocity material-laden gas stream in a confined zone tocause the solid to be reduced in size; discharging gas and solid fromsaid confined impact zone to a classifying zone through a relativelyconstricted passageway to cause translation of pressure energy in theconfined impact zone to velocity in said classifying zone; and,returning particles above predetermined size ranges from saidclassifying zone to the said aspirating zone.

The apparatus for carrying out the method -just described may comprise agenerally cylin- 1 .16% ele siiying chamber near the bottom of which thesolid feed is aspirated into a high velocity gas jet or jets and carriedout of the chamber to an impact anvil located within a confined space.From said confined space a passageway leads back to the classifyingchamber and enters same near its top, directed tangentially therelnto,providing entry of ground solid suspended in the gas stream. The upperportion of the chamber serves as a classifying section in whichparticles larger than predetermined size ranges are rejected from thevortically flowing gas stream and return to the bottom Of the chamber tobe picked up again by the aspirator.

Figure 1 shows diagrammatically, in side elevation, an apparatus whereinthe invention may be practised. Referring to said figure, washed wetsolid I is fed from a conical bottom hopper H through a star feeder l2into a vertically disposed tube l3 projecting well into a cylindricalclassifying and separating chamber M. An inlet pipe I 5 is connected toa source of gas such as superheated steam or compressed air undersuperatmospheric pressure, which source is preferably at a point outsidethe classifying chamber I. Said pipe I5 is centrally located in the feedtube l3 and projects downwardly through the feed tube l3 to a point nearthe conically shaped bottom l6 of the classifying chamber It. The gasinlet pipe l5 terminates in a nozzle H, which, for convenience, may bethreadediy engaged with the end of the pipe I5. The conical bottom iiiof the classifying chamber I4 is attached to a connecting pipe i8projecting into an impact chamber l9 which directs the gas against ananvil which is preferably removable for replacement. Said anvil is madefrom any hard and abrasion resisting material and has its impact surfaceperpendicular to the axis of the connecting pipe l8. A passageway 2!serves to carry gas and particles of the solid from the impact chamberl9 and return the same tangentially into the classifying chamber It. Thepassageway 2| leads into the classifying chamber it near the upperportion thereof, and enters the same approximately tangentially. Anannularly disposed baiile 22 having a circular up-standing lip 23 isarranged in the classifying chamber l4 immediately below the point atwhich the-passageway 2! from the impact zone i9 is attached to the upperpart of the classifying chamber l4.

An off-take pipe 24 from the top of the chamber i4 is provided to carrygas and particles of the .desired size from the chamber l4 anddischarges into a suitable cyclone separator (not shown) or otherreceiving means. The off-take pipe 24 is concentrically disposed withrespect to the feeder tube l3 and projects into the chamber I4 so thatits tip 25 is in approximately the same horizontal plane as the upperedge of the lip 23 on the annular bailie 22 in the classifying chamberll.

In operation, solid, either wet or dry, is fed at a substantiallyuniform rate by a star feeder I2 into the feeding tube i3 and fallsfreely through said tube and the classifying chamber M to the bottomthereof, at which point it is aspirated by high-pressure gas flowing outof the nozzle l1 and is hurled violently against the anvil 20 in theimpact zone IS. The gas and shattered particles then move out of theimpact zone I9 through the passageway 2| and into the upper portion ofthe classifying chamber It. The introduction of said gas tangentiallyinto the chamber l4 induces a circulation of the reduced particles inthe chamber, causing the particles of larger size to l4 and flow aroundthe tip 25 of the off-take pipe 24 and thence out into a cycloneseparator.

The following example illustrates the practice of the invention withanthracite culm. A feed rate of 1100 pounds per hour of coal, containingapproximately ten per cent by weight of water, was maintained into theseparating chamber of the apparatus just described. The star feeder,carrying six paddles, was rotated at a speed of thirty revolutions perminute. Steam under pressure of pounds and at a temperature of 750 F.was introduced into the apparatus at the rate of 2000 pounds per hour. Ascreen analysis Of the feed was: Less than 1% through a 100 mesh and allthrough a 16 mesh.- The temperature of the coal after grinding was350-375 F. The screen analysis of the product showed 96% through a 325mesh screen, 98 through a 200 mesh, and only a trace on 100 meshscreen.- The product gave entirely satisfactory results in use as apowdered fuel for a boiler.

Figures 2 and 3 illustrate modifications which may be made in theapparatus by which the above-disclosed process is practiced.

In Figure 2 the parts 00,, l2, l3, I4, ll. 22,

23, 24, and 25 are all the same as above described for the embodimentillustrated in Figure 1. The impact chamber l9a, corresponding tochamber I9 in Figure 1, is here located concentrically withinclassifying chamber ll. It has a feed opening 26 in its bottom and atubular feed member l8a which is likewise concentric with theclassifying chamber l4 extending therethrough. Said tubular member I8ais flared at its lower end 21 to aid in the aspirating of solidparticles into the gas stream. The anvil 20a is located within theimpact chamber l9a on the side thereof opposite the feed opening 23 andhas its impact surface located perpendicularly to the axis of feed tubel8a. Said impact chamber l9a may advantageously have a conical top 28for convenience in preventing solid particles from piling thereon. Apassageway 2la extends from impact chamber l9a out through the wall ofthe classifying chamber l4 and then reenters same throughan openingwhich may be constricted at the upper end thereof, in the same manner asillustrated and described for the embodiment shown in Figure 1.

A gas conduit l5a is connected to a source of gas at superatmosphericpressure, which gas is preferably dry and heated. This conduit entersthrough the bottom of the classifying chamber l4 and terminates in anozzle 29 which is suitably spaced from the flared portion 21 of thefeeder tube lBa for maximum aspirating effect in view of the size of theparticular device, material being handled, pressure available, and otherrelated factors, all of which are well known and understood.

The operation of this embodiment follows exactly the same principles asabove described for the embodiment shown in Figure 1, and, since thisoperation will be entirely understandable by reference to thedescription presented in onnection with Figure 1 and inspection ofFigure 2, further detailed description will be omitted;

In the embodiment shown in Figure 3 the prln ace-mes ilb, carries theminto the impact chamber lib,

and hurls them against an anvil 20b. The continuing flow of gas carriesthe shattered particles out through a passageway 2lb directed into theupper portion of the classifying chamber II.

N This figure also illustrates a modification in the classificationmeans which is applicable to all three forms. It is more efficient forcertain matlrials and comprises narrowing the classification chamber idand eliminating the baffle 22 and lip 23 tobrovide the classificationmeans as shown in said figure.

However, the general manner of operation is unchanged in that theclassifying chamber, drops out the oversize particles during itsdownward movement and then moves upwardly through the middle of saidchamber carrying the finely pulverized material and goes out through theoff -take pipe 24 as before.

Various methods of feeding may be employed and various kinds ofapparatus can be devised which will hurl the particles of solid at highvelocity against the anvil, collect and classify the product thereof andreturn the oversized one to the raw feed for reprocessing. These variousmodifications will, however, all be within the scope of my inventionboth as a process and apparatus except as the otherwise.

Having thus fully disclosed and described my improved process andapparatus, I claim:

I 1. In apparatus for pulverizing solids, the combination of: aclassifying chamber, a centrally disposed feeder tube ber, and means tointroduce a wet solid to be pulverized into said feeder tube; a pipewithin said feeder tube and extending beyond the projection of saidfeeder tube to a point near the bottom of said chamber for introducing agas under superatmospheric pressure; a tube communicating from thebottom of said chamber with an impact chamber; an anvil in said impactchamber located to be struck by gas under. pressure from saidclassifying chamber; a passageway from said impact chamber communicatingwith said classifying chamber and tangentially directed thereinto in theupper portion thereof; and, an offtake pipe from said classifyingchamber.

2. In apparatus for pulverizing solids, the combination of: aclassifying chamber, a centrally disposed feeder tube extending intosaid chamber, and means to introduce a wet solid to be pulverized intosaid feeder tube; a pipe within said feeder tube and extending beyondthe pro jection of said feeder tube to a point near the bottom of saidchamber for introducing a gas under superatmospheric pressure; a tubecommunicating from the bottom of said chamber with an impact chamber; ananvil in said impact chamber located to be struck by gas under pressurefrom said classifying chamber; a passageway from said impact. chambercommunicating with said classifying chamber and tangentially directedthereinto in the upper portion thereof; an annular baffle plate havingan upstanding lip located within said classifying chamber below thepoint of tangential introduction of fluid and solid extending into saidchamclaims specifically limit thereinto; an offtalre pipe concentricallyarranged with respect'to said annular baile plate and adjacent said lip.

3. In apparatus for pulverizing partially comminuted solids acombination of: an independent impact chamber; an anvil within saidchamber; means to introduce a gas under pressure into said chamber andarranged to direct said gas against said anvil; means to introduce theparticles to be pulverized into said gas stream; a separating chamber; aclosed conduit providing passageway from said impact chamber for leadingall the gas and solidparticles carried therein tangentially into theupper portion of said separating chamber; an annularly disposed baiiiein said separating chamber having an up-standing lip disposedimmediately below the passageway from the impact chamber at its point ofentry into the separating chamber; a centrally disposed oiftake fromsaid separating chamber; means providing communication from the bottomof the said separating chamber to the pointof introduction of the solidfeed into the gas stream flowing to the impact chamber.

4. Apparatus for pulverizing a granulated solid, in wet or dry conditioncomprising in combination: a classifying chamber; adjustable meansgravitationally feeding said solid centrally into said chamber at asubstantially uniform rate; tubular means providing communication fromthe bottom of said classifying chamber to an inde-, pendent and enclosedimpact chamber; an anvil in said impact chamber positioned thereindiametrically from said communicating means and having its face surfacesubstantially perpendicular to the axis of said tubular communicationmeans; a nozzled conduit entering said classifying chamber positionedwith its nozzle adjacent and co-axial with the said tubular means; ameans supplying dry gas to said nozzled vconduit at a relatively highpressure; a closed conduit forming a passageway providing restrictedcommunication between. and leading all the gas and entrained materialfrom, said impact chamber to the upper portion of said classifyingchamber and entering tangentially thereinto; an annular baiile withinsaid classifying chamber located adjacent the lower edge of saidlast-named conduit at its point of entry into said chamber partiallyrestricting communication between the upper and lower portions of saidclassifying chamber and a continuous up-standing lip at the inner mostedge of said baffle forming a cylinder coaxial with said chamber; outletmeans from said classifying chamber co-axial with and of less diameterthan said cylinder.

5. Apparatus for pulverizing a granulated solid in wet or dry conditioncomprising in combination: a classifying chamber; adjustable meansgravitationally feeding said solid centrally into said chamber at asubstant' ally uniform rate; an impact chamber located within said firstchamber and co-axial therewith; means providing communication from saidclassifying chamber into said impact chamber; an anvil in said impactchamber positioned therein diametrically from said communication meansand having its impact surface perpendicular to the axis of saidcommunication means; a nozzled conduit connected with a source of .drygas under superatmosphcric pressure and entering said classifyingchamber; with its nozzle positioned adjacent said communication meansand co-axial therewith; a passageway providing restricted communicationfrom said impact chamber to the upper portion of said classifyingchamber and entering tangentially thereinto; an annular baffie withinsaid classifying chamber located ad- Jacent the lower edge of saidpassageway at its point of reentry thereinto partially restrictingcommunication between the upper and lower portions of said classifyingchamber and having a continuous upstanding lip at its innermost edgeforming a cylinder co-axialwith said chamber; outlet means co-axial withand of less diameter than said cylinder, beginning approximately in thesame horizontal plane with the upper end of said lip and communicatingwith receiving means.

6. Apparatus for pulverizing a solid comprising in combination: acylindrical classifying chamber; means for feeding said solid into saidchamber; an enclosed impact chamber having an opening therein on oneside thereof and an anvil therein on the opposite side thereof; aconduit connected to a source of dry gas at superatmospheric pressurepositioned in line with said opening and perpendicular to said anvil andterminating at a point spaced from said opening for providing a gasstream; means for introducing the heavies of the classified solids fromthe classifying chamber into said gas stream; a single tubularpassageway of uniform cross section and perpendicular to the opening insaid impact chamber for transporting all of the gas and entrainedmaterial from said impact chamber tangentially entering said classifyingchamber; outlet means co-axial with and of lesser diameter than saidclassifying chamber.

7. An apparatus for pulverizing solid particles comprising: a chamberhaving a circular classifying zone and a feeding zone, an independentenclosed impact chamber, means for releasing a gas under pressurethrough an orifice to create a high velocity flowing gas stream havingan as pirating zone in said feeding zone, a conduit ex-' tending atleast part way through said classifying zone, means for introducingmaterial to be ground thereinto, said conduit passing said materialthrough at least a part of said classifying I zone but separated thentherefrom and discharging it for free falling through the rest of saidclassifying zone into the aspirating zone whereby said material isintroduced into the gas stream in said aspirating zone, means forinterposing a block in the path of the high velocity materialladen gasstream in said independent enclosed impact zone, a tubular passagewavtangentially entering said classifyingzone for discharging the gas andentrained material from said independent impact zone to a point in saidclassifying zone opposite a portion of said conduit for translatingpressure in the impact zone to rotational velocity in the classifyingzone, said parts being arranged for returning particles above apredetermined size range from said classifying zone to the aspiratingzone, and discharging from the classifying zone gas and entrainedparticles below said predetermined size.

8. An apparatus for pulverizing a granulated solid comprising incombination: a cyclone chamber having a classifying zone at its upperend and a material collection zone at its lower end; a feeding conduitsubstantially concentric with and extending into and partially throughsaid cyclone chamber, means for feeding said solid into said conduit; anindependent impact chamber having an opening therein and an anvil withinsaid chamber positioned oppositely to and co-axial with said opening; aconduit connected to a source of gas at super atmospheric pressure,

form cross-section throughout its length providing communicationfrom'said impact chamber to the upper portion of said cyclone chamber ata point therein opposite a portion of the feeding conduit; asubstantially annular outlet means coaxial with said feeding conduit andproviding venting from said cyclone chamber beginning at a point abovethe discharge end of said feeding conduit.

9. An apparatus for pulverizing solid particles comprising: a circularcyclone chamber having a classifying zone in its upper portion and amaterial collection zone in its lower portion each in open communicationwith the other, tubular vertical means for introducing solid materialthereinto extending centrally into and at least partially through theclassifying zone in said cyclone chamber, an independent enclosed impactchamber exterior of said cyclone chamber containing an anvil, a conduitconducting a stream of gas under pressure into said impact chamber anddirected against said anvil, said gas stream having an aspirating zoneadjacent said impact chamber and at the bottom of the materialcollection zone, a single closed passageway of uniform cross-sectionthroughout its length providing the only ofitake and only means ofventing gas and entrained material from said impact chamber to saidclassifying zone, said passageway entering said classifying zonetangentially and substantially above the discharge opening of saidmaterial introducing means, all so constructed and arranged that boththe raw and insufliciently pulverized material enter the materialcollection zone and thereby said aspirating zone by gravity from saidclassifying chamber, an annular venting means surrounding andsubstantially concentric with said material feeding means extending intothe classifier a portion of the length of said feeding means.

10. Apparatus for pulverizing a granulated solid comprising incombination: a classifying cham-- her having a material collection zoneat its lower end; means for feeding said solid into said chamber at asubstantially uniform rate; an independent impact chamber exterior ofsaid classifying chamber having an opening therein and an anvil withinsaid impact chamber positioned oppositely to said opening; a conduitperpendicular to said anvil connected to a source of dry gas atsuperatmospheric pressure, terminatingat a point spaced from saidopening and 'co-' axial therewith for providing a gas stream; means forproviding open communication from said collection zone to said gasstream for effecting continuous gravitational passage of said solid fromsaid collection zone to said gas stream and introduction thereinto; apassageway substantially perpendicular to the axis of said opening forleading all the gas and entrained material from saidimpact chamber tothe upper portion of said classifying chamber; outlet means co-axialwith the classifying chamber and providing venting from the upperportion of said classifying chamber.

11. An apparatus for pulverizing solid particles comprising: a circularclassifying chamber, means introducing solid material thereintoextending vertically and centrally into and partially through saidclassifying chamber, an independent enclosed impact chambersubstantially in the center of said classifying chamber and containingan anvil, a tubular member extending into said impact chamberperpendicular to and coaxial with said anvil; a nozzle coaxial with saidtubular member for directing a stream of gas under pressure through saidtubular member into said impact chamber, a single enclosed passageway ofuniform cross section throughout its length for providing the onlyofltake and the only means of venting gas and entrained material fromsaid impact chamber to said classifying chamber, said passagewayentering said classifying chamber tangentially and substantially abovethe discharge opening of said material introducing means, said gasstream adjacent said impact chamber having an aspirating zone at thebottom of and in open communication with said classifying chamber, saidparts so arranged that both the raw and the insufliciently pulverizedmaterial will fail by gravity directly into the aspirating zone. NORWOODH. ANDREWS.

REFERENCES CITED The following references are of record in the file ofthis patent:

Number Number UNITED STATES PATENTS Name Date Marks June 6, 1911McKeivey Dec. 23, 1919 Davis Feb. 19, 1924 Arrowood May 10, 1927 KramerFeb. 23, 1932 Kollbohm Feb. 23, 1932 Hadsel Apr. 19, 1932 Anger Aug. 30,1932 Walton Sept. 6, 1932 Wohlenberg Oct. 18, 1932 Peabody Aug. 8. 1933Anger Mar. 2, 1937 Chesler Mar. 30, 1943 FOREIGN PATENTS Country DateGreat Britain July 19, 1937 Germany Nov. '7, 1929 Germany Aug. 23, 1930Germany Jan. 10, 1933

